Re: [PATCH net] jhash: fix -Wimplicit-fallthrough warnings

[David Miller]

From: Jakub Kicinski 
Date: Fri, 14 Jul 2017 23:03:49 -0700

> GCC 7 added a new -Wimplicit-fallthrough warning.  It's only enabled
> with W=1, but since linux/jhash.h is included in over hundred places
> (including other global headers) it seems worthwhile fixing this
> warning.
> 
> Signed-off-by: Jakub Kicinski 
> ---
> If it looks good, would it be OK to take it via the net tree?

Applied, thanks Jakub.

[PATCH net] jhash: fix -Wimplicit-fallthrough warnings

[Jakub Kicinski]

GCC 7 added a new -Wimplicit-fallthrough warning.  It's only enabled
with W=1, but since linux/jhash.h is included in over hundred places
(including other global headers) it seems worthwhile fixing this
warning.

Signed-off-by: Jakub Kicinski 
---
If it looks good, would it be OK to take it via the net tree?

 include/linux/jhash.h | 29 ++---
 1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/include/linux/jhash.h b/include/linux/jhash.h
index 348c6f47e4cc..8037850f3104 100644
--- a/include/linux/jhash.h
+++ b/include/linux/jhash.h
@@ -85,19 +85,18 @@ static inline u32 jhash(const void *key, u32 length, u32 
initval)
k += 12;
}
/* Last block: affect all 32 bits of (c) */
-   /* All the case statements fall through */
switch (length) {
-   case 12: c += (u32)k[11]<<24;
-   case 11: c += (u32)k[10]<<16;
-   case 10: c += (u32)k[9]<<8;
-   case 9:  c += k[8];
-   case 8:  b += (u32)k[7]<<24;
-   case 7:  b += (u32)k[6]<<16;
-   case 6:  b += (u32)k[5]<<8;
-   case 5:  b += k[4];
-   case 4:  a += (u32)k[3]<<24;
-   case 3:  a += (u32)k[2]<<16;
-   case 2:  a += (u32)k[1]<<8;
+   case 12: c += (u32)k[11]<<24;   /* fall through */
+   case 11: c += (u32)k[10]<<16;   /* fall through */
+   case 10: c += (u32)k[9]<<8; /* fall through */
+   case 9:  c += k[8]; /* fall through */
+   case 8:  b += (u32)k[7]<<24;/* fall through */
+   case 7:  b += (u32)k[6]<<16;/* fall through */
+   case 6:  b += (u32)k[5]<<8; /* fall through */
+   case 5:  b += k[4]; /* fall through */
+   case 4:  a += (u32)k[3]<<24;/* fall through */
+   case 3:  a += (u32)k[2]<<16;/* fall through */
+   case 2:  a += (u32)k[1]<<8; /* fall through */
case 1:  a += k[0];
 __jhash_final(a, b, c);
case 0: /* Nothing left to add */
@@ -131,10 +130,10 @@ static inline u32 jhash2(const u32 *k, u32 length, u32 
initval)
k += 3;
}
 
-   /* Handle the last 3 u32's: all the case statements fall through */
+   /* Handle the last 3 u32's */
switch (length) {
-   case 3: c += k[2];
-   case 2: b += k[1];
+   case 3: c += k[2];  /* fall through */
+   case 2: b += k[1];  /* fall through */
case 1: a += k[0];
__jhash_final(a, b, c);
case 0: /* Nothing left to add */
-- 
2.11.0